The Study of Natural Products

[摘要] This thesis consists of six chapters. A General Introduction is presented at the beginning, dealing briefly with the background of wood chemistry research, the nature of secondary metabolism and the objectives of the study. Furthermore, the biogenesis of diterpenoids, nor-lignans and phenylethylchromones are also discussed. Chapter I concerns a discussion of the constituents of the normal and infected woods of Agathis borneensis. Fourteen compounds from both woods were isolated, including four new compounds 44, 46, 51, 53>. Their structures were elucidated mainly by use of 1H and 13C n. m. r. and mass spectroscopy. The occurrence of xanthones in Calophyllum species is reviewed in Chapter II. This is followed by a discussion of the extractives from the wood and bark of Calophyllum biflorum. Five compounds were isolated, two of which are new compounds 80,82>. The petroleum ether and ethyl acetate extract constituents of the infected wood of Aquilaris malaccencis is discussed in Chapter III. Four phenylethylchromones were isolated, of which compound 42> is a new compound. In addition, a new sesquiterpenoid compound 43> was also isolated. The results of a phytochemical screening of three Dipterocarpus species is described in Chapter IV. The wood extracts of D. costulatus. D. cornutus and D. baudii were investigated. The timber of D. costulatus contains more extractives than the other two Dipterocarpus species. Dipterocarpol was found to be the major compound in all three species. An investigation of the tetranortriterpenoid constituents of Azadirachta indica is discussed in Chapter V. Five tetranortriterpenoids were isolated and compound 22> was identified as a new compound. A detailed description of the preparation of 3-deacetyl-azadirachtin by mild alkaline hydrolysis and its reacetylation to azadirachtin is also given. The final chapter deal with raffinose, a trisaccharide isolated from Delonix regia. The structure was assigned by modern m. m. r. techniques including two-dimensional experiments. The 13C n. m. r. resonances of raffinose peracetate are assigned for the first time.

[发布机构] University:University of Glasgow

[关键词] Organic chemistry